Furniture with top plate

ABSTRACT

A piece of furniture with a top plate configured to be change a height thereof, the piece of furniture includes: a top plate; a pair of left and right leg bodies which supports left and right sides of the top plate. Each of the leg bodies includes a fixed leg column installed on a floor surface, a movable leg column supported by the fixed leg column to be raised and lowered, a gas spring which is extendable and retractable vertically to assist elevation of the movable leg column and fixation of a height position of the movable leg column, and a switch which switches an extendable state and a fixed state of the gas spring. An operating unit which operates the switch is provided in the top plate. A switching synchronizer is provided to simultaneously operate each of the switch when the operating unit is operated.

TECHNICAL FIELD

The present invention relates to a piece of furniture with a top plateand a height of which can be changed by raising or lowering the topplate.

BACKGROUND ART

An over-bed table (a piece of furniture with a top plate) according tothe related art has a gas spring in one of a pair of left and rightextendable and retractable legs (leg bodies), so that when the top plateis raised, a push rod of the gas spring is pushed by an operating lever(operation means) provided at a top side of the extendable andretractable leg to assist raising and/or lowering of the top plate by apressing force of the gas spring. An operating lever is provided at atop side of an extendable and retractable leg without the gas spring, sothat even when an operator is situated at either the left or right sideof the over-bed table, raising and lowering of the top plate can beoperated (for example, see Patent Document 1).

For example, as disclosed in Patent Document 2, in a piece of furniturewith a top plate according to the related art, leg bodies are configuredby a pair of left and right guide rods (outer leg columns), andelevation rods (inner leg columns) which can smoothly move verticallyalong the guide rods. Further, a gas spring is provided in one leg bodyto assist raising and/or lowering of the top plate and fix a height ofthe top plate, and an adjusting means (elevation synchronizing means) isconfigured by a plurality of pulleys (synchronizing pulley members) anda wire (synchronizing wire member) hung on the pulleys, so that it makesdifficult to generate an elevation error in the left and right elevationrods, and the left and right sides of the top plate can be synchronouslyraised with good balance. Further, various synchronizing means andextension synchronizing means (elevation synchronizing means) of thesame type are disclosed in Patent Documents 1 and 3.

PRIOR ART REFERENCE Patent Document

-   [Patent Document 1]: Japanese Patent No. 2761706 (page 3, page 4,    FIG. 2, and FIG. 5)-   [Patent Document 2]: Japanese Patent Application Laid-Open    Publication No. 1998-179266 A (page 3 and FIG. 7)-   [Patent Document 3]: Japanese Patent No. 3681001 (page 4 and FIG. 3)

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In the over-bed table (a piece of furniture with a top plate) describedin Patent Document 1, since a gas spring is provided only in oneextendable and retractable leg (leg body), such a configuration cannotbe applied to a table with a large-sized heavy top plate, requiring thegas spring to be provided in both left and right extendable andretractable legs. However, when the gas springs are provided in both theleft and right extendable and retractable legs, if the pressing timingsof push rods for the gas springs become different, one of the gassprings is extended or retracted first, causing the top plate to betilted.

In the height adjusting means (elevation synchronizing means) of a topplate of a desk described in Patent Document 2, it is required to fix anend of a wire (synchronizing wire member) of the adjusting means or apulley (synchronizing pulley member) to a guide rod (outer leg column).Further, the wire or pulley is accommodated within a cover memberprovided at a side of a leg body to be prevented from being interferedwith a gas spring. Accordingly, a width of the leg body or the likeincluding the cover member increases and a weight thereof alsoincreases. Patent Documents 1 and 3 also have a similar problem.

The present invention has been made in an effort to provide a piece offurniture with a top plate, which is configured such that gas springsare provided in both left and right leg bodies to enable the top plateto be easily raised even if the top plate is heavy and the top plate canbe prevented from being tilted when the top plate is being raised orlowered.

Further, the present invention has been made in an effort to provide apiece of furniture with a top plate, which is configured such thatelevation synchronizing means for synchronously raising and/or loweringleft and right side sections of the top plate and gas springs areaccommodated in the leg bodies compactly to be able to reduce weights ofleg bodies.

Means for Solving the Problem

In order to solve the problem, a piece of furniture with a top plate ofthe present invention includes a top plate and a pair of left and rightleg bodies which supports left and right sides of the top plate, whereina height position is changeable by raising or lowering the top plate,the piece of furniture is characterized in that each of the leg bodiesincludes a fixed leg column installed on a floor surface, a movable legcolumn supported by the fixed leg column to be raised and lowered, a gasspring which is extendable and retractable vertically to assist raisingand lowering of the movable leg column and fixation of a height positionof the movable leg column, and a switching means which switches anextendable state and a fixed state of the gas spring, and an operationmeans which operates the switching means is provided in the top plate,and a switching synchronizing means is provided to simultaneouslyoperate each of the switching means when the operation means isoperated.

According to this feature, a vertical location of the top plate can beadjusted by an operation of the gas spring. Even a heavy top plate canbe easily raised and lowered by two gas springs of both the left andright leg bodies. Since extendable states and fixed states of the leftand right gas springs can be simultaneously switched by the switchingsynchronizing means for operating the switching means at the same time,the top plate is prevented from being tilted due to asynchronousswitching of the gas springs.

The piece of furniture of the present invention is characterized in thatthe switching means serves as an operating member which operates anoperating part of the gas spring and is provided with a flexibleoperating wire member which connects each of the operating member, andthe switching synchronizing means is configured by providing a movablemember which moves a substantially central portion of the operating wiremember in a direction other than a direction in which the flexibleoperating wire member extends.

According to this feature, when the flexible operating wire member ismoved in a direction other than a direction in which the operating wiremember extends by the movable member when the operation means isoperated, left and right ends of the operating wire member connected tothe operating members is moved equally in a direction in which theoperating wire member extends, so that the operating parts of the gassprings can be operated simultaneously. Accordingly, the switchingsynchronizing means can be constituted with a simple structure includingthe operating member, the operating wire member, and the movable member.

The piece of furniture of the present invention is characterized in thatthe movable member is adapted to pull the substantially central portionof the operating wire member, and the substantially central portion ofthe operating wire member smoothly moves on a contact surface of themovable member.

According to this feature, if the operation means is operated, both leftand right ends of the operating wire member is moved toward asubstantially central portion so that both the left and right ends ofthe operating wire member can be moved equally. Further, even when thereis an error between lengths of the operating wire member from themovable member to the operating members, the error can be offset bysmoothly moving the operating wire member on the contacting surface withthe movable member.

The piece of furniture of the present invention is characterized in thatthe substantially central portion of the operating wire member iscoupled to an operating pulley member of the movable member, and avicinity of a portion of the operating wire member coupled to theoperating pulley member is maintained to smoothly move on a maintainingpart fixed to the top plate.

According to this feature, even when an error occurs between the lengthsof the operating wire member from the movable member to the operatingmembers, the operating wire member is moved in a direction in which theoperating wire member extends through rotation of the operating pulleymember, so that the error can be offset. A vicinity of a portion of theoperating wire member coupled to the operating pulley member ismaintained by the maintaining part fixed to the top plate, so that theoperating wire member is prevented from being deviated from theoperating pulley member.

A piece of furniture with a top plate of the present invention, inwhich: a pair of left and right leg bodies which supports left and rightsides of the top plate is configured such that an inner leg column isinserted into and fitted with an outer leg column to allow each leg bodyto be freely extended and retracted vertically; a height position isconfigured to be changed by extending and retracting the leg bodies toraise and lower the top plate; and an elevation synchronizing means thatsynchronizes extending and retracting operations of the leg bodies, thepiece of furniture is characterized in that the elevation synchronizingmeans is constituted with a synchronizing pulley member pivotallyattached to a leg column configured to be raised and lowered from amongthe inner and outer leg columns, and a flexible synchronizing wiremember hung on the synchronizing pulley member, the synchronizing wiremember is connected to a connecting member fixed to a leg columnextending in a vertical direction and installed on a floor surface fromamong the inner and outer leg columns, and the inner leg column isconfigured such that a first accommodating portion accommodating a gasspring, which is extended and retracted vertically to assist anextension and retraction of the leg body and fixation of a heightposition of the leg body, and a second accommodating portionaccommodating the connecting member are provided to be spaced apart fromeach other.

According to this feature, the gas spring accommodated in the firstaccommodating portion, and the connecting member accommodated in thesecond accommodating portion, the synchronizing wire member connected tothe connecting member, or the synchronizing pulley member hung on thesynchronizing wire member are operated without being interfered witheach other. Even when the leg column installed on the bottom surface isany one of the inner and outer leg columns, the leg column can beconnected to the synchronizing wire member by means of the connectingmember extending vertically. Further, the first and second accommodatingportions are formed in the inner leg column, the elevation synchronizingmeans for synchronously raising and/or lowering both left and right sidesections of the top plate and the gas spring can be compactlyaccommodated in the leg body, thereby reducing a weight of the leg body.

The piece of furniture of the present invention is characterized in thata third accommodating portion formed between the first accommodatingportion and the second accommodating portion and having a width narrowerthan those of the first and second accommodating portions is provided inthe inner leg column, and the synchronizing pulley member isaccommodated in the third accommodating portion.

According to this feature, the gas spring accommodated in the firstaccommodating portion, the synchronizing pulley member accommodated inthe third accommodating portion and the synchronizing wire member hungon the synchronizing pulley member are operated without being interferedwith each other. Further, since the third accommodating portion has anarrow width, the first accommodating portion and the secondaccommodating portion can be spaced apart from each other by the thirdaccommodating portion.

The piece of furniture of the present invention is characterized in thata recessed groove extending vertically is formed at an outer surface ofthe inner leg column corresponding to the third accommodation portion,and a guide roller is provided at the recessed groove, and

a slide surface extending vertically is formed at an inside of the outerleg column in order for the guide roller to be smoothly contacted.

According to this feature, the guide roller disposed in the recessedgroove of the inner leg column smoothly contacts the slide surface inthe outer leg column, so that an extending/retracting operation of theleg body can be smoothly performed. The recessed groove can be formed inthe inner leg column using a portion where the third accommodatingportion having a narrow width is provided, so that the guide roller canbe compactly accommodated between the inner leg column and the outer legcolumn.

The piece of furniture of the present invention is characterized in thata pair of upper and lower guide rollers having axes of rotationorienting the same direction and rotated independently are provided inthe recessed groove so that each of the guide rollers smoothly contactswith the slide surface arranged to be opposed.

According to this feature, the pair of guide rollers are disposedbetween the slide surfaces disposed to be opposed to each other andextending vertically, so that the guide rollers can smoothly contactwith the slide surfaces respectively, thereby preventing the leg columnsadapted to be raised and/or lowered from being shaken horizontally.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a table according to a firstembodiment of the present invention.

FIG. 2 is a front view illustrating the table.

FIG. 3 is a left side view illustrating the table.

FIG. 4 is a perspective view illustrating wiring of wire members anddisposition of operating parts.

FIG. 5 is a longitudinal cross sectional view illustrating innerstructures of a right arm and a leg body, taken along line A-A of FIG.4.

FIG. 6 is a longitudinal cross sectional view illustrating an innerstructure of the leg body, taken along line B-B of FIG. 5.

FIG. 7 is a transversal cross sectional view illustrating the innerstructure of the leg body, taken along line C-C of FIG. 5.

FIG. 8 is a partially enlarged view of FIG. 5 illustrating a top part ofthe leg body.

FIG. 9A is a longitudinal sectional view taken along line D-D of FIG. 8.

FIG. 9B is a longitudinal sectional view illustrating a state where agas spring is being pushed by a pressing member.

FIG. 10 is a perspective view illustrating a lower end portion of anelevation rod.

FIG. 11 is a concept view illustrating a state where a guide rollersmoothly contacts a slide surface of a support rod.

FIG. 12A is a plan view illustrating an operating part.

FIG. 12B is a plan view illustrating a state where an operating lever ispulled toward the front side.

FIG. 13A is a longitudinal sectional view taken along line E-E of FIG.12A.

FIG. 13B is a longitudinal sectional view illustrating a state where theoperating lever is pulled to the front side.

FIG. 14 is a concept view illustrating an operating wire member hung ona pulley and a pressing member.

FIG. 15 is a concept view illustrating an elevation synchronizing means.

FIG. 16A is a plan view illustrating an operating part according to asecond embodiment of the present invention.

FIG. 16B is a plan view illustrating a state where an operating lever ispulled toward the front side.

FIG. 17A is a longitudinal sectional view taken along line F-F of FIG.15.

FIG. 17B is a longitudinal sectional view illustrating a state where theoperating lever is pulled toward the front side.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of a piece of furniture with a top plateaccording to the present invention will be described.

First Embodiment

A piece of furniture with a top plate according to a first embodimentwill be described with reference to FIGS. 1 to 17B. Hereinafter, lowerright sides of FIGS. 1 and 4 will be described as a front side (forward)of a table, upper right sides of FIGS. 1 and 4 will be described as aright side of the table 1, right sides of FIGS. 3, 5, 7, 8, 12A, 12B,13A, 13B, 16A, 16B, 17A, and 17B will be described as a front side(forward) of the table, and a lower side of FIG. 14 will be described asa front side (forward) of the table.

Reference numeral 1 of FIG. 1 denotes a table which is a piece offurniture with a top plate to which the present invention is applied.The table 1 includes one sheet of top plate 2 which is laterally long,and one pair of left and right leg bodies 3 supporting left and rightsides of the top plate 2, respectively, and configured to change aheight of the top plate 2 by raising and/or lowering the top plate 2.

As shown in FIGS. 2 and 3, each leg body 3 includes a base leg 4installed on the floor surface to be extended forward and rearward, asupport rod 5 (fixed leg column, outer leg column) provided to beerected from a center of the base leg 4, and an elevation rod 6 (movableleg column, inner leg column) inserted into the support rod 5. A topportion of the support rod 5 is opened, and the elevation rod 6 isinserted into the support rod 5 to be raised or lowered freely withrespect to the support rod 5.

As shown FIG. 4, arms 7 extending forward and rearward are provided atthe top portions of the leg bodies 3, respectively, and attached to thetop portions of the elevation rods 6. The left and right arms 7 areconnected to each other by two connecting rods 8 provided in parallel inforward and rearward direction. The connecting rods 8 constitute legcolumns, and extend substantially linearly between the left and rightleg bodies 3. The top plate 2 is attached to top portions of the arms 7and the connecting rods 8 such that the top plate 2 can be raised as theelevation rods 6 are raised.

Operating parts 9 (operating means) operated by an operator when raisingand/or lowering the top plate 2 are attached to a central portion of alower surface of the top plate 2 (see FIG. 2). The operating parts 9 arespaced apart from each other and attached to two front and rearlocations of the top plate 2 which are situated around a front end and arear end of the top plate 2, so that the operator can operate elevationof the top plate 2 at any place either the front side or the rear sideof the table 1 (see FIG. 4).

As will be described below, the operator lifts or lowers the top plate 2while maintaining a state where an operating lever 10 provided in theoperating part 9 is moved horizontally in a direction far away from thetop plate 2 to freely change a height of the top plate 2.

Next, internal structures of the left and right leg bodies 3 will bedescribed. Since the internal structures of both of the leg bodies 3have substantially the same structure where the front and rear sidesthereof are formed in a reverse state, the right leg body 3 will bedescribed as an example. FIG. 5 is a cross sectional view taken alongline A-A of FIG. 4 and is a longitudinal sectional view viewed from theinner side of the table 1.

As shown in FIG. 5, a connecting member 11 fixed to a base leg 4 isprovided to extend vertically on the front side (the right side of thedrawing) in an inner part of the elevation rod 6, a gas spring 12 whichis extended and retracted vertically is provided on the rear side (theleft side of the drawing) in the inner part of the elevation rod 6.Meanwhile, a lower end of the gas spring 12 is fixed to the base leg 4,and a top end thereof is fixed to a lower surface of the arm 7.

A pulley member 13 (synchronizing pulley member) and a synchronizingwire member 14 constituting an elevation synchronizing means to bedescribed below are provided between the connecting member 11 and thegas spring 12. The pulley member 13 is rotated about a rotation axis 61extending laterally, and is moved vertically by the synchronizing wiremember 14.

Next, the gas spring 12 will be described with reference to FIGS. 5 and8. As shown in FIG. 5, the gas spring 12 has a cylinder 15 encapsulatinggas, and a piston rod 16 disposed within the cylinder 15 to repeatedlyenter into and exit from the cylinder 15. The gas spring 12 is extendedand retracted vertically according to entering and exiting of the pistonrod 16, a vertical length of the gas spring 12 may be changedarbitrarily.

As shown in FIG. 8, the piston rod 16 is operated as a push rod 17provided at a top end of the gas spring 12 is pressed, thus arbitrarilychanging the vertical length of the gas spring 12. A nut 18 attached toa location lower than the arm 7 in the piston rod 16 is secured to alower surface of the arm 7 in a threaded fashion.

Meanwhile, the elevation rod 6 is raised and/or lowered vertically asthe vertical length of the gas spring 12 is changed, and a height of theelevation rod 6 is fixed as the vertical length of the gas spring 12 isfixed. Hereinafter, a state where the push rod 17 is pressed and thusthe piston rod 16 can be extended and/or retracted will be referred toas an extendable state, and a state where the push rod 17 is releasedfrom the pressed state and thus the piston rod 16 is locked (fixed) willbe referred to as a fixed state.

Next, a switching means for switching a state of the gas spring 12between the extendable state and the fixed state will be described withreference to FIGS. 8, 9A, and 9B. FIG. 9A is a cross sectional viewtaken along line D-D of FIG. 8, and is a longitudinal rear crosssectional view where the leg body 3 is viewed from a rear side of thetable 1.

As shown in FIGS. 8 and 9A, a pressing member 19 (switching means,operating member) for pressing the push rod 17 (an operating part) ofthe gas spring 12 is provided within the arm 7.

The pressing member 19 is pivotally attached to a pivot member 20attached to the arm 7, and the pressing member 19 fluctuates verticallywhile taking a pivot shaft 21 extending forward and rearward on a lowerside thereof as an axis thereof.

As shown in FIG. 9A, a top end of the pressing member 19 is formed as awire coupling part 23 to which an operating wire member 22 forfluctuating the pressing member 19 is coupled, and a pressing part 24for pressing the push rod 17 is formed at a part of a lower end of thepressing member 19 corresponding to the gas spring 12.

The operating wire member 22 has an operating wire 25 (operating wiremember, the switching synchronizing means) and a resin tubular member26, and the operating wire 25 is inserted into and passes through thetubular member 26 to be smoothly moved in a direction where theoperating wire 25 extends within the tubular member 26. The operatingwire member 22 is fixed to the arm 7 by a fixing part 27 formed at anend of the tubular member 26.

In the table 1 according to the present embodiment, two operating wiremembers 22 are provided on the front and rear sides. The pressingmembers 19 are provided in the left and right arms 7 respectively, andone operating wire member 22 connects the pressing members 19 to eachother (see FIGS. 4 and 14). The front and rear operating wire members 22are connected to the same pressing member 19, and the front and rearoperating wire members 22 are disposed substantially in parallel to eachother near the pressing member 19.

The operating wire 25 is provided to be longer than a length of thetubular member 26, and the operating wire 25 is exposed to an end of theoperating wire member 22. Tips of the operating wires 25 are stopped bycoupling clasps 28 respectively, and the coupling clasps 28 are coupledto wire coupling parts 23 of the pressing members 19. The wire couplingparts 23 are formed on the front and rear sides of the pressing member19, and the front and rear operating wires 25 and 25 are coupled to thefront and rear wire coupling parts 23, respectively (see FIG. 8). In thepressing member 19, the front and rear wire coupling parts 24(connecting portions) are spaced apart from each other on the front andrear sides, and the pulley member 43 to be described below can bedisposed between the front and rear wire coupling parts 23, that is,between the two operating wire members 22.

As shown in FIG. 9B, if the operating wire 25 is pulled inward, thepressing member 19 fluctuates and the pressing part 24 lowers. Then, thepush rod 17 of the gas spring 12 is pressed so that the piston rod 16turns into an extendable state where the gas spring 12 can be extendedand retracted.

Meanwhile, if the gas spring 12 turns into an extendable state, thepiston rod 16 is lifted by a pressing force of the gas in the gas spring12 so that the arm 7 and the top plate 2 are pushed upward to allow evena heavy top plate 2 to be easily lifted by the operator.

If a state where the operating wire 25 is pulled is released, thepressing part 24 is pushed upward by the push rod 17 and thus thepressing 19 fluctuates and returns. The piston rod 16 is locked to be ina fixed state. Accordingly, the extendable state and the fixed state areswitched therebetween. In order to allow the pressing member 19 toeasily return, a pressing means such as a spring may be provided at aportion of the pivot shaft 21 of the pivot member 20.

Next, the operating part 9 will be described with reference to FIGS. 12Ato 13B. Since the operating parts 9 provided two locations at the frontand rear sides of the top plate 2 have the same structure, the operatingpart 9 provided on the front side will be described as an example. Asshown in FIG. 12A, a fixed member 29 which is fixed to the top plate 2and a movable member 30 which is movable horizontally are provided inthe operating part 9. The operating lever 10 for moving the movablemember 30 by the operator is provided on the front side of the movablemember 30.

The fixed member 29 has a rectangular shape in a plan view, and fourcorner portions of the fixed member 29 are secured to the top plate 2 ina threaded fashion. Two maintaining parts 31 for maintaining theoperating wire member 22 are formed at a rear end of the fixed member29. The movable member 30 combined with the top side of the fixed member29 has a front portion whose a left and right width is smaller than thatof a rear portion thereof.

Two long holes 32 extending forward and rearward are formed on the frontside and rear side of the movable member 30. Bolts 33 inserted into andpassing through the long holes 32 from the top side thereof are fixed tothe fixed member 29, and when the movable member 30 is situated at anormal location shown in FIG. 12A, the bolts 33 are situated at frontends of the long holes 32 respectively.

A substantially semicircular pulley disposing part 34 is formed at arear side of the movable member 30. A pulley 35 (a movable member, aswitching synchronizing means, and an operating pulley member) to whicha substantially central portion of the operating wire member 22 iscoupled is attached to the pulley disposing part 34.

As shown in FIG. 13A, a hole portion 36 formed in the pulley disposingpart 34 of the movable member 30, a central hole 37 of the pulley 35,and a hole portion 39 of a pulley pivoting member 38 attached to themovable member 30 are formed at locations corresponding to one another.The pulley 35 is configured to be rotated about a rotation axis 62thereof extending vertically between the pulley pivoting member 38 andthe pulley disposing part 34.

In the maintaining part 31 of the fixed member 29, a fixed part 40provided at an end of the tubular member 26 of the operating wire member22 is maintained and the operating wire 25 exposed from the fixed part450 is coupled to the pulley 35. A circumferential surface on the frontside of the pulley 35 serves as a contact surface 41 on which theoperating wire 25 of a substantially central portion of the operatingwire member 22 is smoothly moved.

A vicinity of a portion of the operating wire member 22 coupled to thepulley 35 is maintained by the maintaining part 31, so that theoperating wire 25 remains hung on the pulley 35 to be able to beprevented from being deviated from the pulley 35.

As shown in FIGS. 12B and 13B, if the operating lever 10 is pulledforward and thus the movable member 30 is moved to a front location, theoperating wire 25 is smoothly moved in the tubular member 26 so that theoperating wire 25 coupled to the pulley 35 is pulled forward.

Next, an operation during operation of the operating part 9 will bedescribed with reference to the concept view of FIG. 14. Since thepressing members 19 of the left and right leg bodies 3 are connected toeach other though the operating wire member 22 and the operating parts 9are provided at substantially central portions of the front and rearends of the top plate 2, a substantially central portion of theoperating wire member 22 is smoothly moved on the contact surfaces ofthe pulleys 35 of the operating parts 9 to be pulled.

Accordingly, even when there is an error in lengths of the operatingwire members 22 from the movable member 30 to the left and rightpressing members 19, the error is offset as the operating wire members22 are smoothly moved through the contact surface 41 of the pulleys 35in conjunction with rotation of the pulleys 35. The operating wiremembers 22 may be spaced part from the contact surfaces 41 of thepulleys 35. That is, the operating wire members 22 may be moved relativeto the pulleys 35 and the movable members 30.

When the operator pulls the front operating lever 10 forward, theoperating wire 25 coupled to the pulley 25 is pulled forward and leftand right ends of the operating wire 25 are moved inward. The pressingmembers 19 within the left and right leg bodies 3 are operated at thesame time, and thus the extendable state and the fixed state of the gassprings 12 can be switched into each other at the same time (see FIGS.9A and 9B)

Next, the elevation synchronizing means for synchronizing extendable andretractable operations of the left and right leg bodies 3 will bedescribed with reference to FIGS. 5 to 8 and 15. The elevationsynchronizing means for synchronizing vertical movement of the elevationrod 6 is provided in the table 1 according to the present embodiment.FIG. 6 is a cross sectional view taken along line B-B of FIG. 5 and is alongitudinal rear cross sectional view when the right leg body 3 isviewed from the rear side of the table 1.

The elevation rods 6 disposed on the left and right sides can be movedvertically by the same distance respectively by means of the elevationsynchronizing means. Thus, a horizontal state of the top plate 2 can bemaintained when the height of the top plate 2 is changed.

As shown in FIGS. 5 and 6, the pulley member 13 provided between the gasspring 12 and the connecting member 11 inside the elevation rod 6 isrotated about the rotation axis 61 extending leftward and rightward tobe moved vertically by the synchronizing wire member 14.

A pulley member 43 (a synchronizing pulley member) where two front andrear pulleys 42 and 42′ are connected is provided in the arm 7, and thepulley member 43 is rotated about a rotation axis 63 extending forwardand rearward and the front pulley 42 and the rear pulley 42′ can berotated independently.

A ‘U’ shaped bracket 44 when viewed from a side is provided outside thepulley member 43 (see FIG. 8), and the pulley member 43 is secured tothe arm 7 through the bracket 44 (see FIG. 6). The pulley member 43 isdisposed more inside than the pressing member 19, so that the pressingmember 19 does not collide with the pulley member 43 even when thepressing member 19 fluctuates (see FIGS. 9A and 9B).

The synchronizing wire member 14 is coupled to the pulley members 13 and43 to be hung on lower sides of the left and right leg bodies 3 and thetop plate 2. As shown in FIG. 8, a connecting clasp 45 is provided inthe vicinity of the connecting member 11 of the synchronizing wiremember 14, and the synchronizing wire member 14 is connected to a topend of the connecting member 11 through the connecting clasp 45.

As shown in FIG. 5, a stopper 46 is provided at a substantiallyintermediate portion of the connecting member 11. A stopper contactmember 47 is provided on a lower surface of the elevation rod 6, andlifting of the elevation rod 6 stops at a location where the stoppercontact member 47 contacts the stopper 46 (see FIG. 10).

The synchronizing wire member 14 is hung in a U-shaped form from thefront pulley 42 of the pulley member 43 toward the rear pulley 42′through the pulley member 13. The synchronizing wire member 14 extendingfrom the pulley member 43 of the right arm 7 extends toward the left arm7, and is integrally formed hung on the left arm 7 and the leg body 3.

An operation during elevation of the top plate 2 will be described withreference to a concept view of FIG. 15. The elevation synchronizingmeans includes pulley members 13 and 43 and a synchronizing wire member14 connected to the connecting member 11. As mentioned above, the pulleymembers 13 and 43 are pivotally attached to the elevation rod 6 to beraised and/or lowered together with the elevation rod 6.

As shown in FIG. 15, the synchronizing wire member 14 hung on one pulley42 of the upper pulleys 42 and 42′ will be described as a synchronizingwire member 14 a and the synchronizing wire member 14 hung on the otherpulley 42′ will be described as a synchronizing wire member 14 b in thefollowing.

For example, when the elevation rod 6 on the right side of the drawingis lifted, the right pulley member 43 is lifted. Since the synchronizingwire member 14 a is fixed to the connecting member 11 through theconnecting clasp 45, the right pulley 42 is pulled and lifted so thatthe left pulley member 13 is moved in conjunction with the synchronizingwire member 14 a and is lifted by the same distance as the movementdistance of the right pulley 42.

Similarly, when the elevation rod 6 on the left side of the drawing islifted, the left pulley member 43 is also lifted. Since thesynchronizing wire member 14 b is fixed to the connecting member 11through the connecting clasp 45, the left pulley 42′ is pulled andlifted so that the right pulley member 13 is moved in conjunction withthe synchronizing wire member 14 b and is lifted by the same distance asthe movement distance of the left pulley 42′.

In this way, since the synchronizing wire member 14 a and thesynchronizing wire member 14 b are operated at the same time toinfluence each other, there is no possibility of lifting of only one ofthe left and right elevation rods 6, 6 in advance occurs. That is, theleft and right elevation rods 6 and 6 can be synchronized with certaintyto be lifted.

Even when the left and right elevation rods 6 and 6 drop, the leftelevation rod 6 and the right elevation rod 6 are operated to lower inconjunction with each other at the same time by the same distance. Inthis way, since the extensions and retractions of the left and rightelevation rods 6 and 6 are synchronized, the left and right elevationrods 6 and 6 and the top plate 2 can be raised and/or loweredintegrally.

That is, when the height of the top plate 2 is changed in a synchronizedextensions and retractions of both of the leg bodies 3 by the elevationsynchronizing means, the top plate 2 can be raised and/or lowered whilemaintaining the horizontal state thereof without distorting the heightof the top plate 2 on the left and right sides.

Next, disposition of the gas spring 12, the connecting member 11, andthe pulley member 13 in the leg body 3 will be described with referenceto FIGS. 7 and 10. The right side of FIG. 7 will be described as thefront side.

As shown in FIG. 7, a first accommodating portion 48 in which the gasspring 12 is accommodated is formed at a rear side of the elevation rod6 inserted into the support rod 5, and a second accommodating portion 49in which the connecting member 11 is accommodated is formed at a frontside of the elevation rod 6. A third accommodating portion 50 in whichthe pulley member 13 is accommodated is formed between the firstaccommodating portion 48 and the second accommodating portion 49.

In this way, the gas spring 12 accommodated in the first accommodatingportion 48, the pulley member 13 accommodated in the third accommodatingportion 50, and the synchronizing wire member are adapted to be operatedwithout being interfered with each other.

The third accommodating portion 50 has a left and right width narrowerthan those of the first and second accommodating portions 48 and 49, anda recessed groove 51 extending vertically is formed at a portion on theouter surface of the elevation rod 6 corresponding to the thirdaccommodating portion 50.

As shown in FIG. 7, a plurality of guide rollers 52 rotated about arotation axis 64 extending leftward and rightward are attached to foursurfaces including the outer surfaces on the front and rear sides of theelevation rod 6 and the left and right recessed grooves 52. A pair ofupper and lower guide rollers 52, 52, of the guide rollers 52, isrotated independently, and the pair of upper and lower guide rollers 52,52 constitutes one roller part 53.

As shown in FIG. 10, the respective guide rollers 52, 52 of the rollerpart 53 are disposed to be displaced horizontally to some degree, and inthe present embodiment, roller parts 53 are provided at two upper andlower locations of each of the front, rear, left and right surfaces ofthe elevation rod 6 (see FIGS. 5 and 6).

As shown in FIG. 7, grooves 54 are formed at portions of the support rod5 corresponding to the guide rollers 52, and the opposing surfaces ofthe grooves 54 are formed as slide surfaces 55 which the guide rollers52 contact smoothly. Each pair of upper and lower guide rollers 52smoothly contact one slide surface 55 and another slide surface 55respectively.

As shown in the concept view of FIG. 11, the guide roller 52 on theright side of the drawing smoothly contacts the right slide surface 55,and the guide roller 52 on the left side of the drawing smoothlycontacts the left slide surface 55. Accordingly, the elevation rod 6 canbe raised and/or lowered without being shaken horizontally.

When the elevation rod 6 is lifted, the right guide roller 52 is rotatedclockwise and the left guide roller 52 is rotated counterclockwise.Accordingly, an elevation operation of the elevation rod 6 can besmoothly performed.

When the elevation rod 6 is lowered, the right guide roller 52 isrotated counter-clockwise, and the left guide roller 52 is rotatedclockwise (not shown).

Since the recessed groove 51 is formed using a portion of the elevationrod 6 where the third accommodating portion 50 is provided, the guideroller 52 can be compactly accommodated between the elevation rod 6 andthe support rod 5.

Next, an operation of the operating part 9 by the operator to raiseand/or lower the top plate 2 will be described. If the operator pullsthe operating lever 10 of the operating part 9 in a forward direction tomove the movable member 30 to a front location, a substantially centralportion of the operating wire 25 coupled to the pulley 35 is movedforward (see FIG. 12B), and both ends of the operating wire member 22are moved to a central side equally (see FIG. 14).

The left and right pressing members 19, 19 to which the operating wire25 at an end of the operating wire member 22 is coupled are fluctuated,and the pressing part 24 is lowered to press the push rod 17 of the gasspring 12 simultaneously (see FIG. 9B). Then, the left and right gassprings 12, 12 can be extended and retracted at the same time to makethe top plate 2 elevatable.

In this way, since the left and right gas springs 12, 12 are switchedinto an extendable state at the same time, one of the gas springs 12 isprevented from being switched in advance and thus the top plate 2 isprevented from being tilted, due to unevenness of the pressing forces ofthe gas springs 12, 12.

When the operator lifts the top plate 2, the top plate 2 is pushedupward to be lifted while the gas spring 12 remains extended, that is,the operating lever 10 is being pulled. In this case, since an upwardforce is applied to the piston rod 16 by the gas in the gas spring 12,even a heavy top plate 2 can lifted easily.

Since the elevation synchronizing means constituted with the pulleymembers 13 and 43 and the synchronizing wire member 14 is provided, aheight of the top plate 2 can be prevented from being distorted in theleft and right sides. Since the operating part 9 is provided at asubstantially central portion of the top plate 2, the force applied tothe top plate 2 by the operator can be equally applied to the left andright leg bodies.

When the top plate 2 is moved to an arbitrary location and the operatorreleases a hand from the operating lever 10 to return the movable member30 to a normal location, a substantially central portion of theoperating wire 25 coupled to the pulley 35 is moved rearward and thus anend of the operating wire member 22 is equally moved outward.

The left and right pressing members 19, 19 to which the operating wire25 at the end of the operating wire member 22 is coupled are fluctuatedand the pressing part 24 is lifted, thereby releasing the pressings ofthe push rods 17 of the gas springs 12 simultaneously. The left andright gas springs 12, 12 simultaneously become a fixed state to fix alocation of the top plate 2.

Meanwhile, when the operator lowers the top plate 2, the top plate 2 ispushed downward to be lifted while the gas spring 12 remains extendedstate, that is, the operating lever 10 is being pulled.

When the top plate 2 is moved to an arbitrary location and the operatorreleases a hand from the operating lever 10 to return the movable member30 to a normal location, the operating wire 25 coupled to the pulley 35is moved rearward and thus an end of the operating wire member 22 ismoved outward at the same time.

When the left and right pressing members 19, 19 are fluctuatedsimultaneously and the pressing part 24 is lifted, the pressings of thepush rods 17 of the gas springs 12 are released simultaneously. The leftand right gas springs 12, 12 simultaneously becomes a fixed state to fixa location of the top plate 2.

As mentioned above, in the table 1 according to the present embodiment,each leg body 3 has a support rod 5 installed on the floor surface, anelevation rod 6 supported by the support rod 5 to be raised and/orlowered, a gas spring 12 for assisting elevation of an elevation rod 6and fixing a height of the elevation rod 6 while being extended andretracted vertically, and a pressing member 19 for switching anextendable state and a fixed state of the gas spring 12, and a switchingsynchronizing means for simultaneously operating the pressing members 19when a operating part 9 provided in a top plate 2 to operate thepressing member 19 is operated is provided. Therefore, a verticallocation of the top plate 2 can be adjusted by an operation of the gasspring 12, while even a heavy top plate 2 can be easily raised and/orlowered by two gas springs 12 of the left and right leg bodies 3.Further, since the extendable state or fixed state of the left and rightgas springs 12 are simultaneously switched by the switchingsynchronizing means for simultaneously operating the pressing members19, one of the gas springs 12 is prevented from being switched inadvance and to prevent the tilting of the top plate 2.

A switching synchronizing means has a configuration in which thepressing members 19 is allowed to operate a push rod 17 of each gasspring 12, a flexible operating wire member 22 connecting the pressingmembers 19 to each other is provided, and a movable member 30 for movinga substantially central portion of the operating wire member 22 in adirection other than a direction in which the operating wire member 22extends is provided in a operating part 9. Accordingly, when theflexible operating wire member 22 is moved by the movable member 30 inthe direction other than the direction in which the operating wiremember 22 extends when the operating part 9 is operated, left and rightends of the operating wire member 22 connected to the pressing members19 are equally moved in the direction in which the operating wire member22 extends and thus the push rods 17 of the gas springs 12 can beoperated simultaneously. As such, the switching synchronizing means canbe provided in a simple configuration in which the pressing member 19,the operating wire member 22, and the movable member 30 are included.

The movable member 30 can pull a substantially central portion of theoperating wire member 22 and the substantially central portion of theoperating wire member 22 can smoothly move on a contact surface 41 ofthe movable member 30. Accordingly, when the operating part 9 isoperated, both left and right ends of the operating wire member 22 aremoved toward the substantially central portion of the operating wiremember 22 so that both the left and right ends of the operating wiremember 22 are moved equally. Even when there is an error in the lengthsof the operating wire members 22 from the movable member 30 to thepressing members 19, the error can be offset by allowing the operatingwire members 22 to smoothly move on the contact surfaces 41 of themovable members 30.

The substantially central portion of the operating wire member 22 iscoupled to a pulley 35 of the movable member 30 so that the vicinity ofa portion of the operating wire member 22 coupled to the pulley 35 ismaintained in a maintaining part 31 fixed to the top plate 2 to be ableto smoothly move. Accordingly, even when there is an error in thelengths of the operating wire members 22 from the movable member 30 tothe pressing members 19, the error can be offset by allowing theoperating wire member 22 to be moved due to rotation of the pulley 35 ina direction in which the operating wire member 22 extends. Further, thevicinity of a portion of the operating wire member 22 coupled to thepulley 35 is maintained by the maintaining part 31 fixed to the topplate 2, thereby preventing the operating wire member 22 from beingdeviated from the pulley 35.

In the table 1 according to the present exemplary embodiment, theelevation synchronizing means for synchronizing an elevation operationof both leg bodies 3 is constituted with pulley members 13, 43 pivotallyattached to elevation rods 6 of one of inner and outer leg columns,which can be raised and/or lowered, and a flexible synchronizing wiremember 14 hung on the pulley members 13, 43. The synchronizing wiremember 14 is connected to a connecting member 11 fixed to a support rod5 of one of the inner and outer leg columns, and is extended vertically.A first accommodating portion 48 accommodating a gas spring 12 extendingand retracting vertically to assist extension and retraction of the legbody 3 and fix a height of the leg body 3, and a second accommodatingportion 49 accommodating the connecting member 11 are provided in theelevation rod 6 to be spaced apart from each other. Accordingly, the gasspring 12 accommodated in the first accommodating portion 48, and theconnecting member 11 accommodated in the second accommodating portion49, the synchronizing wire member 14 connected to the connecting member11, or the pulley members 13 and 43 on which the synchronizing wiremember 14 is hung are operated without being interfered with each other,and the synchronizing wire member 14 can be connected to the support rod5 by the connecting member 11 extending vertically even when the supportrod 5 is any one of the inner and outer leg columns. Further, since thefirst and second accommodating portions 48, 49 are formed in theelevation rod 6, the elevation synchronizing means for synchronouslyraising and/or lowering left and right sides of the top plate and thegas spring 12 can be compactly accommodated in the leg body 3, achievinglightness of the leg body 3.

A third accommodating portion 50 whose width is narrower than those ofthe first and second accommodating portions 48 and 49 is formed betweenthe first accommodating portion 48 and the second accommodating portion49 of the elevation rod 6. The pulley member 13 is accommodated in thethird accommodating portion 50, so that the gas spring 12 accommodatedin the first accommodating portion 48, the pulley member 13 accommodatedin the third accommodating portion 50, and the synchronizing wire member14 hung on the pulley member 13 are operated without being interferedwith each other. Further, since the third accommodating portion 50 has anarrow width, the first accommodating portion 48 and the secondaccommodating portion 49 can be spaced apart from each other by thethird accommodating portion 50.

A recessed groove 51 extending vertically is formed at a portioncorresponding to the third accommodating portion 50 on the outer surfaceof the elevation rod 6, while a guide roller 52 is provided in therecessed groove 51. Further, a slide surface 55 extending vertically forsmooth contact of the guide roller 52 is formed in the support rod 5 andthe guide roller 52 disposed in the recessed groove 51 of the elevationrod 6 smoothly contacts the slide surface 55 in the support rod 5.Accordingly, an extending/retracting operation of the leg body 3 can besmoothly performed and the recessed groove 51 can be formed in theelevation rod 6 using a portion where the third accommodating portion 50having a narrow width is provided, so that the guide roller 52 can becompactly accommodated between the elevation rod 6 and the support rod5.

Two pairs of upper and lower roller parts 53 independently rotated aboutrotation axes 64 oriented toward the same direction are provided in therecessed groove 51 to smoothly contact the slide surfaces 55 on whichthe guide rollers 52 are disposed to be opposed to each other,respectively. Accordingly, the pair of upper and lower roller parts 53are disposed between the slide surfaces 55 disposed to be opposed toeach other and extending vertically so that the guide rollers 52smoothly contact the slide surfaces 55, the elevatable leg columns whichcan be raised and/or lowered without being shaken horizontally.

Second Embodiment

Next, a piece of furniture with a top plate according to a secondembodiment of the present invention will be described with reference toFIGS. 16A to 17B. FIGS. 16A to 17B are views illustrating a operatingpart 9′ according to the second embodiment of the present invention, andthe configuration except for the operating part 9′ is the same as thatof the first embodiment and thus a description thereof will be omitted.

As shown in FIGS. 16A to 17B, a fixed member 29′ fixed to the top plate2 and a movable member 30′ movable horizontally are provided in theoperating part 2, and a operating lever 10′ for moving the movablemember 30′ by an operator is provided on the front side of the movablemember 30′.

The fixed member 29′ having a rectangular shape when viewed from the topis secured to the top plate 2 in a threaded fashion, and the movablemember 30′ is disposed above the fixed member 29′. As in the firstexemplary embodiment, a long hole 32′ extending forward and rearward isformed at a front side of the movable member 30′ so that a bolt 33′inserted into and passing through the long hole 32′ from the top side isfixed to the fixed member 29′. An operating wire 25 is coupled to apulley 35 provided in the movable member 30′ on a rear side so that themovable member 30′ is moved to a front side through operation of theoperating lever 10′.

As shown in FIG. 17A, a front portion of the operating lever 10′ isformed with a plate portion, and an pulling portion 57 for pulling themovable member 30′ is provided at a rear portion thereof. The pullingportion 57 has a substantially triangular shape when viewed from a side,and a lever pivot portion 58 at a top end thereof is pivotally attachedto a lever attaching portion 59 provided on a lower surface of the topplate 2.

A pivot shaft 60 is provided at a lower portion of the pulling portion57 to be attached pivotally at a rear side of the movable member 30′.When the movable member 30′ is situated at a normal location shown inFIG. 17A, an end of the plate portion 56 of the operating lever 10′orients downward.

As shown in FIG. 17B, when the operator pulls the plate portion 56 ofthe operating lever 10′ upward, the operating lever 10′ is fluctuatedabout the lever pivoting portion 58 and the pivot shaft 60 is movedforward to move the movable member 30′ to a front location.

As a substantially central portion of the operating wire member 22coupled to the pulley 35 is moved forward, as mentioned above, left andright pressing members 19, 19 connected by the operating wire member 22are operated simultaneously and left and right gas springs 12, 12 areswitched into an extendable state.

When the operator releases a hand from the manipulator lever 10′ and themovable member 30′ returns to a normal location, the operating wire 25coupled to the pulley 35 is moved rearward and an end of the operatingwire member 22 is equally moved outward so that the gas spring 12 isswitched into a fixed state.

Meanwhile, since a fluctuating direction of the operating lever 10′ anda direction of raising the top plate 2 are the same in the operatingpart 9′ according to the second embodiment, when the operator operatesthe operating lever 10′ to adjust a height of the top plate 2, theoperator can raise the top plate 2 as it is while gripping a corner ofthe top plate 2 together with the operating lever 10′, such that aheight of the top plate 2 can be easily adjusted.

Although the embodiments of the present invention have been describedwith reference to the drawings, a detailed configuration of the presentinvention is not limited to the embodiments and may be modified or addedwithout departing from the gist of the present invention.

For example, although a table has been exemplified as a piece offurniture with a top plate to which the present invention is applied inthe embodiments, any piece of furniture with a top plate which can beraised and/or lowered may be a desk, and the present invention can beapplied to a shelf or other items.

Although the gas spring 12 is operated by pressing the push rod 17(operating part) in the exemplary embodiments, an operation type of thepush rod (operation part) is not limited to the embodiments and aconfiguration where the gas spring 12 is operated by horizontally movingthe push rod (operating part) may be adopted.

Although a pulley 35 having a contact surface 41 on which the operatingwire member 22 is smoothly moved is used in the embodiments, it will besufficient if a contact surface which is a circumferential surface onthe front side is formed. Otherwise, the pulley 35 may be replaced by amember having a substantially semicircular shape when viewed from thetop.

Although two operating parts are provided at both front and rear sidesof the top plate 2 of the table 1 in the embodiments, one operating part9 may be provided at one of the front and rear sides.

Although two operating parts are provided at both front and rear sidesof the top plate 2 of the table 1 in the embodiments, one operating part9 may be provided at one of the front and rear sides.

Although the elevation rod 6 is inserted into and fitted with thesupport rod 5 installed on the floor surface in the embodiments, thesupport rod 5 may be inserted into and fitted with the elevation rod 6while the elevation rod 6 serves as an outer leg column and the supportrod 5 serves as an inner leg column.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 table (furniture with a top plate)    -   2 top plate    -   3 leg body    -   5 support rod (fixed leg column, outer leg column)    -   6 elevation rod (movable leg column, inner leg column)    -   9, 9′ operating part (operating means)    -   11 connecting member    -   12 gas spring    -   13 pulley member (synchronizing pulley member)    -   14 synchronizing wire member (synchronizing wire member)    -   17 push rod (operating part)    -   19 pressing member (switching means, operating member)    -   25 operating wire (operating wire member, switching        synchronizing means)    -   30, 30′ movable member    -   31 maintaining part    -   35 pulley (movable member, switching synchronizing means,        operating pulley member)    -   41 contact surface    -   42, 42′ pulley    -   43 pulley member    -   48 first accommodating portion    -   49 second accommodating portion    -   50 third accommodating portion    -   51 recessed groove    -   52 guide roller    -   55 slide surface    -   64 rotation axis

1. A piece of furniture with a top plate configured to be change aheight thereof, the piece of furniture comprising: a top plate; and apair of left and right leg bodies which supports left and right sides ofthe top plate, wherein each of the leg bodies includes a fixed legcolumn installed on a floor surface, a movable leg column supported bythe fixed leg column to be raised and lowered, a gas spring which isextendable and retractable vertically to assist raising and lowering ofthe movable leg column and fixation of a height position of the movableleg column, and a switch which switches an extendable state and a fixedstate of the gas spring, and an operating unit which operates the switchis provided in the top plate, and a switching synchronizer is providedto simultaneously operate each of the switch when the operating unit isoperated.
 2. The piece of furniture of claim 1, wherein the switchserves as an operating member which operates an operating part of thegas spring and is provided with a flexible operating wire member whichconnects each of the operating member, and the switching synchronizer isconfigured by providing a movable member which moves a substantiallycentral portion of the operating wire member in a direction other than adirection in which the flexible operating wire member extends.
 3. Thepiece of furniture of claim 2, wherein the movable member is adapted topull the substantially central portion of the operating wire member, andthe substantially central portion of the operating wire member smoothlymoves on a contact surface of the movable member.
 4. The piece offurniture of claim 2, wherein the substantially central portion of theoperating wire member is coupled to an operating pulley member of themovable member, and a vicinity of a portion of the operating wire membercoupled to the operating pulley member is maintained to smoothly move ona maintaining part fixed to the top plate.
 5. A piece of furniture witha top plate, the piece of furniture comprising: a pair of left and rightleg bodies which supports left and right sides of the top plate isconfigured such that an inner leg column is inserted into and fittedwith an outer leg column to allow each leg body to be freely extendedand retracted vertically, wherein a height position is configured to bechanged by extending and retracting the leg bodies to raise and lowerthe top plate; and an elevation synchronizer that synchronizes extendingand retracting operations of the leg bodies, wherein the elevationsynchronizer is constituted with a synchronizing pulley member pivotallyattached to a leg column configured to be raised and lowered from amongthe inner and outer leg columns, and a flexible synchronizing wiremember hung on the synchronizing pulley member, the synchronizing wiremember is connected to a connecting member fixed to a leg columnextending in a vertical direction and installed on a floor surface fromamong the inner and outer leg columns, and the inner leg column isconfigured such that a first accommodating portion accommodating a gasspring, which is extended and retracted vertically to assist anextension and retraction of the leg body and fixation of a heightposition of the leg body, and a second accommodating portionaccommodating the connecting member are provided to be spaced apart fromeach other.
 6. The piece of furniture of claim 5, wherein a thirdaccommodating portion formed between the first accommodating portion andthe second accommodating portion and having a width narrower than thoseof the first and second accommodating portions is provided in the innerleg column, and the synchronizing pulley member is accommodated in thethird accommodating portion.
 7. The piece of furniture of claim 6,wherein a recessed groove extending vertically is formed at an outersurface of the inner leg column corresponding to the third accommodationportion, and a guide roller is provided at the recessed groove, and aslide surface extending vertically is formed at an inside of the outerleg column in order for the guide roller to be smoothly contacted. 8.The piece of furniture of claim 7, wherein a pair of upper and lowerguide rollers having axes of rotation orienting the same direction androtated independently are provided in the recessed groove so that eachof the guide rollers smoothly contacts with the slide surface arrangedto be opposed.